By almost any measure, people living in poor neighborhoods, especially children, get the short end of the stick.

They’re exposed to more gun violence, less open space, more dysfunctional homes and schools, fewer neighborhood services and more undesirable infrastructure (freeways, power plants, water treatment facilities, etc.) than their counterparts in more affluent places.

That’s why the work of a dynamic inner-city pediatrician named Nadine Burke Harris is getting so much attention. Since opening a clinic in San Francisco’s Bayview neighborhood a few years ago, Burke Harris has won plenty of praise – and funding that she’s used to open the Center for Youth Wellness on Third Street.

Building on research by Kaiser Permanente, Burke Harris is pioneering a study of how chronic exposure to “toxic stress” affects people, starting in infancy. Toxic stress among youth is caused by “adverse childhood experiences,” things like having a parent with mental illness, a father behind bars, domestic violence, friends shot or killed by gangs. These situations trigger the “fight or flight” response, according to Burke Harris. With that comes the long-term release of higher levels of stress hormones such as adrenaline and cortisol.

“It affects the brain architecture of younger children, and it can affect not just psychological health, but also the immune system,” says Burke Harris in an interview for “KQED Newsroom.” Toxic stress, she says, can also explain kids acting out in school. That in turn can lead to children being misdiagnosed with things like attention deficit hyperactivity disorder (ADHD) when in fact it’s their brains reacting – normally – to chronic stress.

This is a big deal and it’s pushing school administrators to rethink policies that lead kids, especially African American students, to be suspended for a vague category of behavior known as “willful disobedience.”

Data compiled by EdSource from the 30 largest school districts in California found that nearly half, 48 percent, of student suspensions in California during the 2011-12 school year were for willful defiance.

Statistics show that kids of color are disproportionately targeted. A San Francisco Chronicle article noted that 58 percent of the San Francisco students suspended for willful disobedience in 2011-12 were African-American, although they account for just 11 percent of district enrollment.

Los Angeles has banned the use of the willful disobedience suspension altogether. And other school districts are following suit. (In a related issue, KQED has reported on how some Bay Area school districts are using mindfulness and meditation to help kids break cycles of self-destructive behaviors). In fact, school suspensions are now falling statewide as policies change and administrators realize they simply don’t work.

Scott Shafer reported on this story for “KQED Newsroom,” which is a weekly news magazine program on television, radio and online. Watch Fridays at 8 p.m. on KQED Public Television 9, listen on Sundays at 6 p.m. on KQED Public Radio 88.5 FM and watch on demand here.